Every spring, Chinas cities are plunged into chaos, as all at once, a tidal wave of humanity attempts to return home by train. It is the Chinese New Year. The wave is made up of millions of migrant factory workers. The homes they seek are the rural villages and families they left behind to seek work in the booming coastal cities. It is an epic spectacle that tells us much about China, a country discarding traditional ways as it hurtles towards modernity and global economic dominance.